1. Field of the Invention
The present invention relates to an uninterruptible power supply which is suitable for ensuring that electronic devices such as a computer and a server operate continuously upon failure of a commercial (AC) power supply which serves as a power source for the electronic devices.
2. Description of the Prior Art
With the proliferation of OA (office automation), there is an increasingly higher need for integration of a variety of information (data). To respond to this need, an uninterruptible power supply is provided in order to ensure the operation of an electronic device such as a computer used as an information processing apparatus and a controller in a variety of applications or a peripheral device associated therewith, or such as a server for holding or controlling data in a network system. The uninterruptible power supply is disposed between an associated electronic device and a commercial (AC) power supply, which serves as a power source for the electronic device, such that the uninterruptible power supply powers the electronic device when the commercial power supply fails.
For reference, the uninterruptible power supply is configured to charge its rechargeable battery cells for storing electric energy therein in a normal state, and to retrieve the electric energy from the rechargeable battery cells for powering the electronic device when the commercial power supply fails.
However, since a lead rechargeable battery is typically used as a rechargeable battery cell, conventional uninterruptible power supplies generally become inevitably large and heavy. In addition, the lead rechargeable battery has several problems remained unsolved from an environmental point of view, such as its short lifetime, danger of leaking, and so on, for use as a rechargeable battery cell which is incorporated in an uninterruptible power supply. Also, a conventional uninterruptible power supply operates independently of an associated electronic device, and only powers a power supply unit of the electronic device upon power failure, so that the electronic device cannot detect the state of the rechargeable battery cell in the uninterruptible power supply such as a charge energy, lifetime and so on.
It is an object of the present invention to provide a simple and compact uninterruptible power supply which is capable of ensuring the operation of an electronic device while monitoring the state of a rechargeable battery.
It is another object of the present invention to provide an uninterruptible power supply which is capable of indicating to an electronic device and/or a user of the electronic device, a charging state of a rechargeable battery which is normally charged by the power from a commercial power supply and is responsible for powering the electronic device to ensure the operation of the electronic device when the commercial power supply fails.
It is a further object of the present invention to provide an uninterruptible power supply which is capable of ensuring a stable operation of the rechargeable battery.
An uninterruptible power supply according to the present invention comprises a power supply unit for generating DC power at a predetermined voltage from AC power supplied from the outside to supply the DC power to an electronic device, and a rechargeable battery unit including rechargeable battery cells for storing the power supplied thereto from the power supply unit for supplying the electronic device with the power stored in the rechargeable battery upon service interruption of the AC power. Particularly, the rechargeable battery unit comprises a battery state monitoring unit for monitoring a state of the rechargeable battery cells, and communicating means for notifying the electronic device of Information indicative of the state of the rechargeable battery detected by the battery state monitoring unit.
Specifically, the rechargeable battery cells comprise nickel-metal hydride rechargeable batteries. The battery state monitoring unit comprises functions of detecting a battery voltage, a charge current and/or a battery temperature of the rechargeable battery cells, determining a fully charged state of the rechargeable battery cells based on the information detected thereby, and calculating a charge capacity and/or a lifetime of the rechargeable battery cells. Then, the communication means is configured to notify the electronic device of at least one of a battery voltage, a battery temperature, a charge current, a discharge current, a battery capacity, a lifetime, the number of discharges, and a replacement time of the rechargeable battery cells, as the information indicative of the state of the rechargeable battery cells.
In a preferred aspect of the present invention, the rechargeable battery unit comprises a charge controller for controlling charging of the rechargeable battery cells in accordance with a battery voltage and/or a battery temperature of the rechargeable battery cells detected by the battery state monitoring unit.
Also, in a preferred aspect of the present invention, the power supply unit comprises a first invertor for converting the AC power supplied from the outside to AC power for driving a primary winding of an insulating transformer, a DC voltage stabilizer circuit for retrieving power from a secondary winding of the insulating transformer to generate a predetermined DC stabilized voltage, a charging unit for retrieving power from a ternary winding of the insulating transformer for use in charging the rechargeable battery cells, and a second invertor for DC/AC converting the power supplied from the rechargeable battery cells for driving the ternary winding.
The rechargeable battery unit comprises a power supply monitoring unit for monitoring a state of the power supply unit.
Further, in a preferred aspect of the present invention, the rechargeable battery unit comprises performance determining means for determining backup performance of the rechargeable battery cells for the electronic device in accordance with a battery temperature of the rechargeable battery cells and the power consumption by the electronic device, and result outputting means for outputting the result of determination. Particularly, the performance determining means is configured to calculate the power consumption by the electronic device from the current value supplied to the electronic device from the power supply unit, and to determine based on the amount of used power and the battery temperature of the rechargeable battery cells whether or not the rechargeable battery cells are capable of supplying the electronic device with backup power which can compensate the operation of the electronic device.
Specifically, the result output means is implemented as a display unit for displaying the result of determination as to the backup performance of the rechargeable battery cells for the electronic device, or notifying means for notifying the electronic device body of the result of determination.
Further, in the uninterruptible power supply according to the present invention, the power supply unit and/or the rechargeable battery unit comprise an alarm function for detecting an interruption of the AC power supplied from the outside to inform the interrupted AC power. The alarm function includes means for informing the interrupted AC power through a visual display and/or rumbling, and resetting means for stopping the information.
Also, the rechargeable battery unit in the uninterruptible power supply according the present invention comprises charge energy detecting means for detecting a charge energy of the rechargeable battery cells, charging/discharging detecting means for detecting a charging/discharging state of the rechargeable battery cells, failure detecting means for detecting a failure of the rechargeable battery cells and/or the power supply unit, charge energy display means for displaying the charge energy of the rechargeable battery cells detected by the charge energy detecting means in multiple stages, charging/discharging display means for displaying the charging/discharging state of the rechargeable battery cells detected by the charging/discharging detecting means, and alarming means for informing a failure detected by the failure detecting means.
The charge energy display means is configured to divide the charge energy of the rechargeable battery cells into n stages (n is a natural number equal to or larger than two), wherein the charge energy display means includes n display segments corresponding to the respective stages, which are selectively driven to display the charge energy in multiple stages. The charging/discharging display means comprises a function of displaying a charging state and a discharging state of the rechargeable battery cells in different display forms, and stops the display when the rechargeable battery cells reach a full charge.
Further, the alarming means is configured to inform a failure of the rechargeable battery cells and/or the power supply unit continuously until a reset instruction is given after detecting the failure. The charge energy detecting means in turn is configured to maintain the same output as that generated when the full charge is detected to drive the charge energy display means even if the charge energy detecting means detects a reduction in the charge energy due to a self discharge of the rechargeable battery cells after the full charge of the rechargeable battery cells has been detected.
In a preferred embodiment of the present invention, the uninterruptible power supply comprises a cooling fan implemented as incorporated in a housing which integrally accommodates the electronic device, the power supply unit, and the rechargeable battery unit for cooling down at least one of the electronic device, the power supply unit and the rechargeable battery unit. The power supply unit or the rechargeable battery unit comprises a fan lifetime detecting function for determining a lifetime or a state of the cooling fan for notification to the electronic device.
The rechargeable battery unit is integrally incorporated and packed in a case which is mounted in a drive bay previously prepared for a peripheral device in the housing, and mounted in the drive bay of the housing for use therein.
The rechargeable battery unit comprises a cooling fan for cooling down the rechargeable battery cells, and a fan controller for controlling the operation of the cooling fan. Particularly, the fan controller is configured to detect the temperature of the rechargeable battery to operate the cooling fan. Further, the fan controller preferably comprises a function for forcedly disabling the cooling fan to operate when the rechargeable battery cells are being charged.